David Johnson-Davies

This is a 12-key numeric keypad for use in a range of microcontroller projects (Figure 1). It has the advantage that you only need one analogue input to interface it. It's on a small...

Figure 1 shows a simple tester, based on an ATtiny202, a piezo buzzer, and an LED, for checking circuit wiring or tracing out the tracks on a PCB: Figure 1. The Tiny Continuity...

An adjustable load in Figure 1 provides a constant-current load for testing power supplies and batteries. It allows you to set the load current to up to 1.05 A, using a potentiometer, and displays the...

This article describes a portable breadboard-friendly adjustable power supply, designed as an ideal supply for Arduino projects and other low-power circuits. It is capable of providing from 0 V to 5.5 V at...